Final answer:
Spain and Portugal's strict colonial governance and trade monopoly, established during the early colonization of the Americas, left their ships and settlements vulnerable to privateer attacks by competing European powers.
Step-by-step explanation:
The ways in which Spain and Portugal pursued colonization and regulated their empires made them susceptible to attacks by privateers in the New World and Africa. Both countries were among the earliest to establish colonies in the Americas, using the technologies of the compass, the astrolabe, and the caravel to navigate and claim territories. They set strict controls on trade, directing all treasures and profits directly back to the mother countries, which led to a rigid system of governance over their colonies. This tight control provided the impetus for other European nations to attack Spanish and Portuguese ships and settlements in an attempt to gain access to the lucrative trade routes and commodities.
The Treaty of Tordesillas and the Treaty of Zaragosa divided the New World between Spain and Portugal, granting them a monopoly over certain trade routes and territories. However, this official division did not prevent other emerging European powers, hungry for wealth and resources, from challenging Iberian dominance. Privateers, sponsored by rival nations such as England, France, and the Netherlands, targeted the slow and heavily loaded merchant ships returning from the Americas with gold, silver, and other goods, capitalizing on the long communication and travel times that Spanish and Portuguese fleets faced.